Apparatus for drying materials in paste form



S. BOGATY Jan. 28, 1958 Q APPARATUS FOR DRYING MATERIALS IN PASTE FORMFiled Oct. 21, 1953 2 Sheets-Sheet l v Jan. 28, 1958 s QGATY APPARATUSFOR DRYING MATERIALS IN PASTEFORM Filed Oct. 21,1953

f J? I 5 v 3 1a 2/ r J e o e a e 0e 0 o%%%%%%% United States Patent '0APPARATUS FOR DRYING MATERIALS IN PASTE FORM Stanislaus Bogaty,Philadelphia, Pa., assignor to Proctor & Schwartz, Inc., Philadelphia,Pa., a corporation of Pennsylvania Application October 21,1953, SerialNo. 387,490

4 Claims. (Cl. 34-225) .This invention relates-to new andnsefulimprovements in apparatus for dryingmaterials in the form orconsistency of paste.

The principal object of the present invention is to provide a novelmethod for drying materials in paste form which is elficient, andbotheconomical and practical for commercial production requirements.

Another object of the invention isto provide a novel apparatus forcarrying out the method.

These and other objects of the invention and the various features anddetails of the construction and operation thereof are hereinafterfullysetforth and described with reference to the accompanyingdrawings,in which:

Fig. l'is a plan view of'apparatus embodying the present invention fordrying materials in paste form and consistency in accordance with themethod of the present invention, a portion of thetop of the dryer havingbeen cut-away to illustrate certain details ofthe construction;

:Fig. 2 is a side elevational view of the disclosure in Fig. 1;

Fig. 3 is an enlarged sectional view taken on line 3-3, Fig. 1; and

Fig. 4 is an enlarged sectional view taken 'on line 44, Fig. 3.

In accordance with the present invention the material to'be dried isdeposited in the form of a relatively plastic or viscous mass or pastein a plurality of continuous ribbons 1 upon an endless conveyor 2 ofheat-conducting material such as, for example, stainless steel ofsufliciently' thin gauge to render it flexible and enable it to passabout the usual rolls or pulleys on which endless conveyors customarilyare mounted. The ribbons 1 of the. material extend longitudinally of theconveyor upon and are disposed in spaced'parallel relation transverselythereof.

.The ribbons 1 of the'material are dried by passing them' through dryingapparatus, generally designated 3, which is constructed and operable inaccordance with the present invention. Referring to the drawings, thedrying apparatus 3 of the present invention comprises a housing orenclosure 4 including top wall 5, opposite end walls- 6 and 6a andopposite side walls 7 and 8, respectively. The conveyor 2 with theribbons 1 thereon enters the dryer 3 at the lefthand end thereof withrespect to Fig. 1 of the drawings and emerges from the dryer at therighthand end thereof.

The interior of the dryer 3 is sub-divided by transverse verticalpartitions 9 and 10 into three substantially identical sections A, B andC, respectively. Mounted in each ofthe sections A, B and C of the dryer3 in overlying relation to the conveyor 2is a hood structure 11. Asshown in Fig. 3 of the drawings, in each section the, hood 11 is in thegeneral form of a truncated pyramid which is divergent downwardly froman inlet opening'12 for air at the top thereof to the lower end of thehood which extends longitudinally thefulllen'gth'o'f the-section and hasa width transversely-of the dryer which is substantially'coextensivewith the width of the underlying-conveyor 2. The hood 11 in each sectionis supportedfrom a horizontal partition 13.

overlying-the top of the hood 11 in each sectionof the dryer'and incommunication with the air inlet opening 12 thereto is an air chamber 14into which air isdischarged laterally through control dampers :15fromafan or blower 16 driven by a suitable motor 17 mounted on the top 5of the dryer housing. The partition member 13 alsosupports the airchamber 14 and fan or blower 1 6.

A vertical partition 18 is mounted below the horiz'ontal partition 13and extends longitudinally centrally of each section of the dryer to"sub-divide the upper portion of the section below thehorizontalpartition 13 into separate zones .for movement of the drying air inopposite directions.

An air inlet port 19 to each of the sections'Aand B of thedryer'isprovided in the side wall .8 of the dryer housing and the'amountof air admitted to the sections through the ports 19 is controlled bymeans of louvers or shutters 20. Mounted horizontally in each ofsections A, B and C of the dryer and supported between the side wall8thereof and vertical partition 18 is a heating elemen't'21for heatingthe drying air.

By reason of the construction and arrangement described, air dischargedor admitted to the lower portions of the sections rises upwardly betweenthe dryer wall 8 and partition 18, passes through the heaters 21 wherethe temperature of air is raised to the desired degree. The heated airthen continues its upward passage through an opening 13a in thepartition 13 to the intake of the fan or blower 16 from which it isdischarged laterally and passes through the control louvers or shutters15 to the air chamber 14. From the chamber 14 the heated air passesdownwardly into and through the hood 11 and is discharged from thebottom of the hood through a series of transversely extending narrowelongated nozzles 22 arranged in spaced parallel relation longitudinallyof the dryer section. The discharge nozzles 22 may be formed by stampingthe same in the bottom plate 23 of the hood 11, for example, as shown inFig. 4 of the drawings.

As shown, the nozzles 22 are disposed transversely of the conveyor 2 andthe direction of travel of the ribbons 1 of the material thereon and thelength of the nozzles. 22 is such that the nozzles extend coextensivewith the width of the said conveyor and entirely overlie the ribbons 1thereon. By virtue of this construction and arrangement, the heateddrying air passing downwardly through the hood 11 is discharged throughthe nozzles 22 perpendicularly into impinging contact with the uppersurface of the ribbons 1. The drying air then flows laterally inopposite directions across the ribbons on the conveyor and downwardlyabout the lateral edges of the conveyor 2 into the lower portion of thedryer section.

A predetermined portion of the spent drying air in sections A and B isreheated and recirculated in the manner previously described, and thebalance is exhausted from the dryer. For this purpose there is providedin the lower portion of each section A and B of the dryer an exhaustduct '24 having inlet openings 25 in the top thereof for the air. Theexhaust ducts 24 extend longitudinally beneath the conveyor 2 the entirelength of each section A and B, respectively. The exhaust air isconducted from ducts 24 by ducts 26 to an exhaust manifold. 27 whichextends longitudinally above the dryer housing and has its outlet endconnected to the intake of an exhaust fan or blower 28.

In some cases, in order to prevent'the two outermostribbons 1 ofmaterial adjacent the opposite side edges of. the conveyor 2 from dryingtoo rapidly and at a faster rate than-the -more inwardly disposedribbons 1, it has been found-desirable-to partially reduceor throttlethe air discharged from the nozzles 22 directly onto the surface ofthese outermost ribbons 1. In accordance with the present invention thismay be accomplished'effectively by partially covering the dischargenozzles 22 adjacent the outermost ribbons-1 only of the conveyor 2', -bya perforate bafiie or like structure29. Such a baflie' may consist, forexample, of one or more thicknesses of screening-andin practicesatisfactory results have been obtained byemployingltwo thicknesses of16 meshscreening arranged, for example, .as shownin Fig. .3 of thedrawings. This construction and. arrangement servesto throttlet-thedischargedfromithe end portions of the nozzles 22 sufliciently toretardthe rate of .drying of.the.outermost ribbons lsothat they dry atsubstantially thers'ame rate asthe innermost ribbons. t i t i Theheaters 21 inieach of the sections ofthedryer are controlled byconventional .temperature-responsive instruments to heat the ,dryingsairpassing .therethrough and provide a suitable drying temperature for theparticular material at the discharge nozzles 22.. The temperaturerequired in any given case depends upon the speed of traveloftheconveyor 2,; the consistency and thickness of the particular ribbonsof the material being dried and thehumidity of the inlet'air, highertemperatures being employed in the summer season because of therelatively high humidity conditions existing in that season, and lowertemperatures being employed in the other seasons and in periods ofrelatively low humidity. The construction and arrangement of the fan orblower 16 and the hoed 1 11 issuch as to discharge air; from the nozzles22 at high velocity.

In addition to the temperature control provided in each of the sectionsA, B and C of the dryer, provision is also made for controlling therelative humidity in the-central section B. This may be accomplished,for example, by controlling the amount of air exhausted from section B,for example, by means of bafile or shutters 32 provided in the exhaustmanifold 27 (see Fig. 2) or by means of a water spray (not shown)mounted within the section. Either such device may be controlledmanually or automaticallyin conventional manner'by standard instrumentsand controls readily available commercially.

In practicing the invention, the material in paste form is depositedupon the conveyor 2 in ribbons l having a predetermined depth orthickness and these ribbons are thoroughly dried during passage throughsuccessive sections A, B and C of the dryer. Inthe processof drying, thethickness or depth of the ribbons is reduced. Immediately prior toemerging from the dryer, the steel conveyor may be cooled, for example,by passing it in contact with a chilled or refrigerated roll, for thepurpose of removing any tackinessin the dried'ribbons and also to shrinkthe ribbons slightly to facilitate their separation and removal from theconveyor. The dried ribbons of the material are then doctored orotherwise separated from the conveyor 2 and wound upon suitable mandrelsaccording to the conventional practices.

' I claim:

7 1. A dryer for materials in paste form comprising a housing, meanssubdividing said housing into a succession of drying sections, anendless conveyor passing entirely through the housing and the severaldrying sections thereof to convey thin layers of the materialsuccessively through said sections, a plurality of narrow elongateddischarge nozzles for drying air in each section of the dryer overlyingthe conveyor and disposed in spaced parallel relation lengthwise of theconveyor with the individual nozzles extending transversely thereof,said nozzles being disposed to discharge drying air downwardlyperpendicular to the plane of the conveyor, and perforate membersdisposed in the air stream at the opposite end portions of the dischargenozzles operable to partially throttle the drying air discharged throughsaid nozzle end .portionsandthereby retard therateof dryingofthe outerportions of the material on ,the conveyor so that they dry atsubstantially the same rate as the inner portions thereof. t

2. A dryer for materials in paste form comprising a housing, meanssubdividingfsaidhousing into a succession-of drying sections, an endlessconveyorpassing entirely throughthe' hous'i the several drying 'sectionsthereof to convey thin layers of the material successively through 'saidsections; a *pmram of gna'rrow elongated 'dischargerrozzlesfordryingaiir ineach section of the dryer overlying the conveyorand 'extending'in spaced parallel relation lengthwise of theconveyorwith the individual nozzles extending transversely thereof, saidnozzles being disposed to discharge the drying air downwardlyperpendicular to the plane of the conveyor, means in each section toheat the drying air to a predetermined temperature, meansin each section-to force --the heated drying air through the dischargenozzles-at a'selectedvelocity, and baffle means in each sectionextending'longitudinally of the conveyor intermediate the opposite sideportions of -the'convey'or 'and the overlying'end-portions of thedischarg'enozzles top'arltially throttle the discharged drying air andthereby-retard the rate of drying of the outer; portions of;. thematerialion the conveyor'sothat they dry at substantially thesame rateas the inner'-por-- tions thereof;

3. A dryer for materials' impas'telform comprising a housing, meanssubdividing saidhousing'into a succes-' sion of drying sections,,anendless conveyor passing en-- tirely through the housing and theseveral drying sections thereof to convey thin layers ofthe materialsuccessively through said sections, a plurality of narrow elongateddischarge nozzles for drying air in each section of thedryeroverlyingtheconveyor and extending in spaced parallelrelationlengthwise of the conveyor with the individual nozzles extendingtransversely thereof, said nozzles being disposed to discharge thedrying air downwardlyper v pendicular to the plane ofithe conveyor, andbaffle' means in each section extending longitudinally of theconveyorintermediate; the opposite side portions of the conveyor and theoverlying end portions of the discharge nozzlesto partially throttle thedischarged drying air and thereby retard the rate of drying of the outerportions of the ma-' through the housing and the several drying sectionsthere-'- of to convey thin layers of the material successively throughsaid sections, a plurality of narrow elongated discharge nozzles fordrying air in each section of the'dryer; 'overlying the conveyor'a'ndextending in spaced parallel relation lengthwisev of the'conveyor withthe individualnozzles extending transversely thereof, said nozzles beingdisposed to discharge the drying air downwardly perpendicular to theplaneof the conveyor, means in each sec.-

tion to heat the drying air to a predetermined temperature, means ineach section to force'the heated drying through the discharge nozzles ata selected velocity, baffle means in each section extendinglongitudinally of the conveyor intermediate the' opposite side portionsof the conveyor and the overlying end portions of the discharge nozzlesto partially throttle the discharged drying ail-land. thereby retard therate of drying of the outer portions of.

thematerial on the conveyor so that they dry at substanf tially the samera 13.5 theinner portions thereof, and an. exhaust air duct extendinglongitudinally beneath "the conveyor. in at least s'ome'pf saidsections, and exhaust I meansconnectedjto each 'of said ducts in saidsections.

- it B ferssssa ntq eu ne as ,1.

References Cited in the file of this patent UNITED STATES PATENTSHopkins July 30, 1912 Fosbraey June 29, 1915 5 Field Nov. 9, 1920Braemer July 28, 1925 6 Brabaek Nov. 7, 1933 Bogaty Jan. 4, 1944 DorschMay 20, 1947 Shegda Apr. 1, 1952 Gillis Feb. 10, 1953 Brabaek Oct. 6,1953

